[Bug tree-optimization/37312] New: -Os significantly faster than -O2 on test case

[andi-gcc at firstfloor dot org]

[component might be wrong]

The appended test case is significantly faster with -Os -funroll-all-loops
(~5%) versus -O2 -funroll-all-loops in gcc 4.4 ( gcc version 4.4.0 20080829;
that
is shortly after the IRA merge) on a Core2 (Merom) 

In earlier gcc versions they are about the same performance. The -Os
improvement
is against all earlier versions (good!) but it should be in -O2 too.

I tried -fno-tree-pre as it was suggested and it didn't make a difference.


-- 
           Summary: -Os significantly faster than -O2 on test case
           Product: gcc
           Version: 4.4.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: tree-optimization
        AssignedTo: unassigned at gcc dot gnu dot org
        ReportedBy: andi-gcc at firstfloor dot org
  GCC host triplet: x86_64-linux
GCC target triplet: x86-64-linux


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=37312